The present invention relates generally to compositions and methods of treating diabetes. More specifically, the present invention relates to a method for providing nutrition, or a nutritional supplement, to a patient having diabetes without substantially increasing blood glucose levels.
Diabetes Mellitus is a chronic disorder affecting carbohydrate, fat, and protein metabolism. It is characterized by hyperglycemia and glycosuria resulting from a defect or deficient insulin secretory response. The number of patients diagnosed as diabetic was estimated in 1985 to be 10 million in the United States alone, with the figure increasing at a rate of 6% per year. Two major variants of the disease exist.
One variant, seen in about 10% of all idiopathic diabetics is referred to as insulin dependent diabetes mellitus (IDDM) or juvenile onset diabetes. This variant is frequently manifested for the first time in youth and is characterized by progressive loss of insulin secretory function by beta cells of the pancreas and hence a progressive "dependency" on exogenous insulin for the maintenance of carbohydrate metabolism. (This characteristic is shared by those non-idiopathic, or "secondary" diabetics whose disorder have their origins in pancreatic disease.)
The second variant of idiopathic diabetes is referred to as non-insulin dependent diabetes mellitus (NIDDM) or adult onset diabetes mellitus. This variant accounts for the remainder of the idiopathic diabetic population.
All diabetics, regardless of their genetic and environmental backgrounds or age of onset of the disease, have in common an apparent lack of insulin or inadequate insulin function. Because transfer of glucose from the blood to the muscle and fat is insulin dependent, diabetics lack the ability to utilize glucose adequately. Further, because glycogenolysis is ordinarily inhibited by insulin, the rate of glycogenolysis is elevated in diabetics. Both of these "derangements" from normal metabolic events lead to the accumulation of glucose in the blood (hyperglycemia) to the point where renal glucose reabsorption capacity is exceeded and glycosuria occurs. A major source of energy for the diabetic becomes fatty acids derived from triglycerides stored in fatty tissue.
In the liver, fatty acids are oxidized to ketone bodies which are circulated and used as an energy source by the tissues. In the IDDM patient and sometimes the NIDDM patient, the rate of formation of the ketone bodies may exceed their rate of utilization and ketosis along with metabolic acidosis may occur.
Since tissues appear to be starving for glucose, dietary tissue sources of protein are used in glycogenesis. Anabolic processes such as synthesis of glycogen, triglycerides and proteins are "sacrificed" to catabolic activities including glycogenolysis, gluconeogenesis and mobilization of fats. Thus, the diabetic state which has its origins in a "simple" insulin defect, results in widespread metabolic disturbances having long term pathological effects on nearly all organs and tissues of the body. Indeed, the diabetic state is one of the prime contributors to deaths caused by myocardial infarction, renal failure, cerebrovascular disease, atherosclerotic heart disease, and systemic infections.
The hyperglycemic and glycosuric conditions of the diabetic disease may be treated by a manipulation of the diet, control of body weight, and regulation of physical activity. In some diabetics, particularly those suffering from NIDDM, the hyperglycemic and glycosuric conditions can be treated by oral administration of antihyperglycemic agents such as derivatives of sulfonylureas, sulfonamides, biguanides and other compounds. For diabetics suffering from IDDM and advanced NIDDM, however, therapy has focussed on administration of exogenous insulin.
Of course, the nutritional management of diabetes is of great concern. The American Diabetes Association has published guidelines for nutritional management of diabetes mellitus. These guidelines suggest that sufficient calories be given to a patient to achieve and maintain reasonable weight.
Pursuant to the ADA (1986 Guidelines), the diet may include up to 55%-60%, based on calories, as carbohydrates. The protein content of the diet recommended for people with diabetes in approximately 12%-20% of the total calories. The fat content of the diet is recommended to be less than 30% of the total calories. Of this polyunsaturated fats are recommended up to 10%, saturated fats recommended at less than 10%, and mono-unsaturated fats will make up the remaining percentage of the fat at a range of 10%-15%.
ADA guidelines 1994 revision are more flexible regarding percentage of calories from carbohydrates, but emphasize even further the need for an adequate lipid intake.
In many situations, it may be necessary to support a diabetic patient with an enteral diet or supplement. These diets can either be administered through a nasogastric tube or other external means or provided in a liquid form that the patient drinks. Such formulations may be necessary when patients are hospitalized and/or in other situations where the patients are unable to meet necessary dietary requirements without a nutritional formulation or supplementation.
Presently, a formulation on the market for a diabetic patient is Glucerna.RTM. sold by Ross Product Division, Abbott Labs. See U.S. Pat. No. 4,921,877. Glucerna.RTM. provides approximately the following macronutrient profile: protein 16.7% of the calories; carbohydrate 33.3% of the calories; fat approximately 50% of the calories. The fat in Glucerna.RTM. is provided solely through long-chain triglycerides. Specifically, the fat is provided as 85% of the calories being safflower oil and 15% of the calories being soybean oil. The caloric density of Glucerna.RTM. is approximately 1 cal/ml.
The inventors of the present invention do not believe that presently available formulations satisfactorily meet the nutritional needs of the diabetic patient.